A contestant from NBC's The Voice is denying she sexually assaulted another female singer.

On Monday Melanie Martinez, who appeared on the reality competition series in 2012, was accused by Timothy Heller of forcefully performing oral sex and using a sex toy on her.

In a statement on Twitter, Martinez said she was "horrified and saddened" by the accusations.

"What she and I shared was a close friendship for a period of time," she continued. "We came into each other's lives as we were both starting our careers as artists, and we tried to help each other."

Heller, formerly of the band Dresses, disclosed on social media that, after the two became friends, Martinez pressed her about her sexuality, despite Heller's insistence she had a boyfriend. In June 2015, it culminated in an assault. "I never said yes. I said no, repeatedly," Heller wrote. "But she used her power over me, and broke me down. Just so there is no confusion, I was molested by my best friend."

Heller said she was inspired to come forward by the numerous accounts of women naming their assaulters. "Girls can rape girls," she wrote. "Best friends can rape best friends."

She later told Newsweek she withheld going public with her story earlier because, "I loved her even after it happened, and I had this sick need to protect her."

Martinez doesn't deny the relationship but says Heller "never said no to what we chose to do together." She added that, while they have parted ways, "I am sending her love and light always."

Martinez auditioned for Season 3 of The Voice singing Britney Spears's "Toxic." Adam Levine, Cee Lo Green and Blake Shelton all hit the "I Want You" button, though she ultimately chose Levine as her coach.